Background: Several studies have shown that plant saponins promoted osteoblast differentiation and improved osteoporosis. In the current study, Sea Cucumber Saponin (SCS) with a purity of 80% was extracted from Filipino sea cucumber, with a similar structure to plant saponins.

Objective: This study aims to investigate the effects of SCS on bone formation in vitro and ex vivo.

Results: SCS significantly promoted osteogenic differentiation and mineralization of MC3T3-E1 cells, as well as new osteoid formation in neonatal mouse calvarias ex vivo. qRT-PCR results indicated that SCS markedly down-regulated the expression of C/EBPα* and PPARγ at the levels of transcription, which demonstrate that SCS inhibits the trans-differentiation of MC3T3-E1 cells to an adipocytic phenotype. Moreover, further studies revealed that SCS increased the expression levels of Runx2 and OSX. The mechanism revealed that SCS induced the expression of BMP2 and p-Smad1/5, which indicated that SCS facilitated osteogenesis via activating the BMP2/Smads signaling pathway.

Conclusion: SCS promoted osteogenic differentiation of pre-osteoblasts by activating the BMP2/ Smads molecular pathway, providing a theoretical basis for the development of sea cucumber saponins for the treatment to bone loss diseases such as osteoporosis.

背景：多项研究表明，植物皂苷可促进成骨细胞分化并改善骨质疏松症。在目前的研究中，从菲律宾海参中提取了纯度为80%的海参皂苷（SCS），其结构与植物皂苷相似。

目的：本研究旨在研究 SCS 对体外和离体骨形成的影响。

结果：SCS 显着促进 MC3T3-E1 细胞的成骨分化和矿化，以及离体新生小鼠颅骨的新类骨质形成。qRT-PCR结果表明SCS在转录水平显着下调C/EBPα*和PPARγ的表达，这表明SCS抑制MC3T3-E1细胞向脂肪细胞表型的转分化。此外，进一步的研究表明，SCS 增加了 Runx2 和 OSX 的表达水平。该机制揭示SCS诱导BMP2和p-Smad1/5的表达，表明SCS通过激活BMP2/Smads信号通路促进成骨。

结论：SCS通过激活BMP2/Smads分子通路促进前成骨细胞的成骨分化，为开发海参皂苷治疗骨质疏松等骨丢失疾病提供理论依据。